User Manual

Then there will be a pop-up prompt to upgrade to the official default firmware of
no signal enhancement function, we choose "NO", (of course, if you choose
"YES", the operation will fail and the previous interface will be restored):
Whether to upgrade to the official default firmware
After waiting for a few seconds, the following operation interface will be entered:
Enter the visual operation interface of the Bluetooth host
Next, developers can operate "Holyiot-21017" according to their needs:
Operate according to needs
This point, the introduction of the conventional usage of "Holyiot-21017" has
been completed.
2. The firmware upgrade of Holyiot-21017 (USB-DFU)